San Joaquin River Restoration Project

Adult Spring–Run Chinook Salmon Return Monitoring

V-shaped net weir used to direct fish through the infrared fish counter at the entrance of the San Joaquin River Restoration Area.

V-shaped net weir used to direct fish through the infrared
fish counter at the entrance of the San Joaquin River
Restoration Area. USFWS Photo

Since 2014, the California Department of Fish and Wildlife has released juvenile spring-runChinook Salmon into the San Joaquin River Restoration Area (SJRRA) to facilitate spring-run reestablishment.

The USFWS Lodi Field Office, conducts annual adult spring-run Chinook Salmon return monitoring (March – May) at the entrance of the SJRRA to evaluate the success of juvenile releases and inform adaptive management actions.

Since 2016, our field staff has deployed a v-shaped net weir and electronic fish counter to passively monitor for adult spring-run Chinook Salmon returning to the SJRRA. This system directs fish moving up-stream through an infrared fish scanner that captures a silhouette image of passing fish.

Fish silhouettes used to monitor salmon return, USFWS image

Our staff then analyzes these silhouette images using computer software to determine the relative number and timing of adult Chinook Salmon returns in a given year. See USFWS image left.

Currently, fish passage barriers within the SJRRA preclude returning adults from accessing the upper spawning reaches of the SJRRA near Friant Dam.  Therefore, our current monitoring efforts are used to initiate adult trap and haul efforts to move fish past these barriers into the upper spawning reaches.

File Size Report Title Year Format
814KB SJRRP 2016 Adult Spring Run Return Monitoring 2016 PDF